When Cirion of Gondor called upon Eorl of the Éothéod for aid, the young chieftain resolved to assemble his army and ride south. He mustered an éoherë of more than seven thousand riders, nearly the entire force of his land, and set out southwards through the Vales of Anduin. The famous Ride of Eorl took nine days, and at the end the Riders fell upon the rear of the invading Balchoth and saved the realm of Gondor. In reward, StewardCirion granted them the wide land of Calenardhon in the north of Gondor. That land became Rohan, and the Riders of Eorl who settled there became the first of the Rohirrim.